breaking news overseas. Escalation of violence in Ukraine. The government blaming pro-russian they call them terrorists. Martha Raddatz is in Washington with the latest. Good morning, Martha. Reporter: Good morning, George. This is one of the deadliest attacks in weeks. And it happened at a checkpoint manned by Ukrainian forces in that part of; the country. Journalists saw bodies of the dead and about 30 wounded, scattered across fields near the checkpoint. The witnesses say the troops were attacked by pro-russian insurgents. Ukrainian armored vehicles were set on fire. A military helicopter had to swoop in to rescue the wounded in grave condition. And rebel commanders are showing off weapons they seized like trophies. There's also sporadic fighting elsewhere in the east. This attack comes in the context of Russian troops actually pulling back from the border, correct? Reporter: U.s. Officials say they see no mass withdrawal of Russian troops from the border. But the nato secretary-general, says there has been some activity, which may suggest they are preparing to withdraw. And of course, we have the upcoming elections this weekend. And more violence is expected. Okay. Martha Raddatz, thanks very

This transcript has been automatically generated and may not be 100% accurate.